Survival of mouse embryos after vitrification depending on the cooling rate of the cryoprotectant solution.

The aim of the study was to determine the relationship between the rate of cooling of eight-cell mouse embryos to the temperature of liquid nitrogen (-196 degrees C) and their developmental capacity after thawing on the basis of their ability to leave the zona pellucida ('hatching') during in vitro culturing. Eight-cell embryos were obtained from superovulated female mice and divided into three experimental and one control group. Embryos from the experimental groups were cryopreserved by the vitrification method using ethylene glycol as cryoprotectant. The vitrification protocols used in the study differed in the rate of cooling of the cryoprotectant solution. Embryos from the first group were frozen in conventional 0.25-ml plastic straws, those from the second group in pipetting 'tips', and embryos from the third group, placed in vitrification solution, were introduced dropwise directly into liquid nitrogen. The control group of embryos was cultured in vitro without freezing in a culturing medium in an environment consisting of 95% air and 5% CO2. The developmental capacity of thawed embryos was assessed on the basis of their ability to leave the zona pellucida ('hatching') after three days of in vitro culturing. In the control group 95.1% of embryos 'hatched'. A significantly higher number of embryos that 'hatched' after thawing was observed in the group introduced dropwise directly into liquid nitrogen (60.0%) compared to the group frozen in pipetting 'tips' (37.9%). The group frozen in straws yielded significantly the lowest proportion of 'hatching' embryos (8.1%). These results showed that increasing cooling rates during vitrification of embryos improved their survival.

Growth and development of follicles in different phases of the oestrous cycle in cows in relation to the presence of the corpus luteum and an oestrogen-dominant follicle.

In this work recruition and growth of follicles and quality of the largest ones were determined and compared in the individual stages of the bovine oestrous cycle (stages I, II, III and IV - days 1-4, 5-10, 11-17 and 18-21, respectively) in relation to the presence of the corpus luteum and an oestrogen-dominant follicle on the ovary. The maximum proportions of small (< 4.9 mm), medium-sized (5.0-9.9 mm) and large (> 10 mm) follicles were observed in stages IV (93.4%), I (16.6%) and III (4.8%), respectively. The results of our study revealed the presence of the large oestrogen-dominant follicle that have negative effects upon the presence of another large follicle on the ovary and upon the recruition of small (< 4.9 mm) follicles. On the contrary, the presence of a large oestrogen-dominant follicle positively influenced the occurrence of 5-9.9 mm follicles in all stages of the cycle. No effects of the CL were observed upon the presence of medium-sized and large follicles. Although the differences were insignificant, negative effects of the CL were observed in relation to the occurrence of small (< 4.9 mm) follicles.

[The effect of steroidal dominance on cAMP, cGMP, progesterone and 17 beta-estradiol levels in the fluid of the largest follicle]. / Vplyv steroidnej dominancie na koncentrácie cAMP, cGMP, progesterónu a 17 beta-estradiolu v tekutine najväcsieho folikulu.

Concentrations and mutual correlations of the cyclic adenosin monophosphate (cAMP), quanosin monophosphate (cGMP), progesterone (P4) and 17-beta-estradiol (E2) were studied in the fluid of the largest follicles in cows, in dependence on the steroid dominance: estrogen-dominant (ED), progesterone-dominant (PD) follicles. Mean cAMP and cGMP concentrations in the follicular fluid in the estrogen-dominant follicles were significantly higher than in the progesterone-dominant follicles; in both cases at P less than 0.01. Significant positive correlation between cAMP and cGMP at P less than 0.001 was stated in the evaluation of the correlations. The cAMP and cGMP concentrations were in significantly negative correlations with the P4 concentration at P less than 0.05, or P less than 0.01 and in significantly positive correlations with the E2, at P less than 0.05. The stated correlations suggest a close mutual relation between cyclic nucleotid and E2, or P4 when the follicles' quality changes.

[Types of 3d cerebral ventricle ependyma in sheep and their localization using segment analysis]. / Typy ependýmu III. mozgovej komory u ovce a ich lokalizácia pomocou segmentovej analýzy.

Attention was focused to the determination of the topographical locality of different ependyma types and determination of their extent by the method of segment analysis. Brain samples of five sheep of the Slovak Merino breed were studied. Excised brains were transversally cut into segments from the frontal pole at 5mm intervals. The eighth, ninth and tenth slices were cast in paraffin and were cut in simultaneous series at 300 microns intervals, the cutting thickness being 10 microns. The paraffin slices were stained with haematoxylin-eosine, Gömöri's chromium haematoxylin, and by the aldehyde fuchsine method after Gömöri. Nine types of ependymal epithelium of the third cerebral ventricle were observed, according to the kind and arrangement of cells. Remarkable differences were found in the occurrence of the types of cells and in their arrangement in the ependyma at the level of the arch of the side walls and bottom of the ventricle within each segment and within the extent of the studied transversal cuts. From the viewpoint of the regulation of hypophysial functions, a significant difference exists in the structure and organization of ependyma at the locality of recessus supraopticus, recessus infundibularis and recessus mammillaris. The results of our study are in agreement with findings in laboratory animals and enrich our previous findings.

[The effect of repeated administration of carbetocin (Depotocin, Spofa) in the first days postpartum on levels of thyroxine, triiodothyronine, 17 beta-estradiol, progesterone and on fertilization]. / Ucinok opakovanej aplikácie karbetocínu (Depotocin, Spofa) v prvých dnoch po pôrode na koncentrácie tyroxínu, trijódtyronínu, 17 beta-estradiolu, progesterónu a na koncepciu bahníc.

Application of new procedures in the sphere of the control of sexual functions requires an extension of present knowledge of postparturient endocrinium or endogenic factors comprised in postparturient physiology of sexual activity. According to recent data, oxytocin, besides its uterotonic and luteolytic activity, acts as an ovarian factor in the local intrafollicular regulation of stereidogenesis and as a modulator of uterine secretion of prostaglandines. Based on present knowledge of oxytocin effects, this study was aimed at investigation of the influence of repeated carbetocin (Depotocin inj. Spofa) administration on the dynamics of changes in thyroxine (T4), triiodothyronine (T3), 17 beta-estradiol (E2), progesterone (P4) concentrations and their mutual correlations from the 36th hour till the 51st day after parturition. Simultaneous study of a possible delayed influence of applied carbetocin on conception of ewes after oestrus evocation on day 51 after lambing was carried out. Nineteen ewes of the Slovak Merino breed, lambed in the first decade of February, were assigned to the experimental (n = 9) and to the control group (n = 10). Experimental ewes were subjected to repeated postparturient carbetocin treatment at the dose 0.07 mg per animal. The first dose was applied i. m. in 24 hours, and the second in 72 hours after parturition. On day 51 oestrus was induced in nine ewes of each group by combined treatment with chlorsuperlutin (Agelin, vaginal pessaries, Spofa) and PMSG (500 I.U./animal). On the day of PMSG application ewes were housed together with rams for the period of the next six days. Samples of blood were taken 24 hours before parturition (-1st day), up to 36 h after parturition and on days 4, 7, 14, 17, 21, 25, 34, 42 and 51 after parturition. Concentrations of T4, T3, E2 and P4 were determined by commercial kits RIA-test-T4; RIA-test-T3; RIA-test-ESTRA and RIA-test-PROG (URVJT Kosice). Animal of the control group showed variations of T4 concentrations (Tab. I, Fig. 1) at the level of original values (59.4 +/- 9.69 nmol.l-1) up to the 21st day with the exception of temporary drop on day 4 and rise on day 7, insignificant compared to the -1st day. T4 concentrations of the control group displayed an intermittent increasing trend with the statistically insignificant peak after 36 h and on day 17, compared to the -1st day. After the 21st day controls revealed a sustained moderate increase while the experimental ewes displayed a decline of its concentrations until the 51st day.(ABSTRACT TRUNCATED AT 400 WORDS)

[Nuclear volume of cells in the stratum granulosum and theca folliculi interna of the largest dominant and atretic tertiary follicles in sheep during the selection process]. / Objem jadier buniek zrnitej vrstvy a vnútorného puzdra najväcsieho dominantného aj atretického terciárneho folikulu oviec v procese selekcie.

According to available literary data, an increased nuclear volume of endocrine gland cells, various structures of the diencephalon and endocrine ovarial structures could be observed when the respective organs and structures were more active; a decreased nuclear volume was revealed when the activity of the respective organ or its structure was suppressed (Mess, 1962; Maracek and Arendarcik, 1976, 1978). Attention was paid to the karyometric analysis of follicular cells of the stratum granulosum (SG) and secretory cells of the theca folliculi interna (TFI) during selection of the dominant ovulatory follicle (DOF). The aim of this study was to determine differences in hte nuclear volumes of the granulosa follicular cells and the secretory cells of the inner theca of the DO1F in comparison with the largest atretic follicles (AF) as well as to verify the use of karyometric variance analysis for the evaluation of the selection process of the dominant ovulatory tertiary follicle. Histological sections were prepared from large DOF and AF from the ovaries of 18 sheep aged 3-5 years and held under standard conditions of a controlled herd. Control group I (n = 3) consisted of Wallachian sheep on day 15 of the sexual cycle (day 0). Excisions of ovaries from the animals of the experimental group (n = 3) were made on day 16 of the cycle after i.m. treatment with 120 micrograms GnRH 10 and 7 hours prior to sampling. Control group II (n = 3) consisted of Tsigai sheep at the 9th or 10th day of the oestrous cycle (hour 0) and three experimental groups (n = 3 each) consisted of Tsigai sheep 24, 48 and 72 hours after i.m. treatment with 125 micrograms cloprostenol. After excision the ovaries were fixed in neutral formaline, cut into 4 mm thick transverse segments and subjected to standard histological processing. After staining with Harris' HE the 5-7 microns thick sections were karyometrically evaluated at a magnification of 2200 x according to the method of Palkovits (1961) using the PC programme Karyotest 03 (Maracek et al., 1991). 200 cells were evaluated from each sample and both cell types; altogether 7200 cells were examined. GnRH treatment (Dirigestran inj. Spofa) increased the nuclear volume of follicular cells (SG) in the dominant ovulatory follicle in the process of selection (Tab. I, Fig. 1). The former, however, reduced the nuclear volume not only of the SG follicular cells of LAF (Tab. II, Fig. 2) but also of the secretory cells of both the DOF and AF theca interna (Tab. II, Figs. 3, 4). Cloprostenol treatment (Oestrophan inj. Spofa) affected the follicular cells of the granulosa in the dominant ovulatory follicle.(ABSTRACT TRUNCATED AT 400 WORDS)

[Dynamic changes in hematologic parameters in the blood of sheep during estrus synchronization and in the subsequent early pregnancy]. / Dynamické zmeny hematologických parametrov v krvi oviec pri synchronizácii ruje a v nadväznom case ranej gravidity.

Observation of hematological indices which are a reflection of physiological processes in the individual phases of the reproductive cycle, presents one of the methods of controlling the homeostasis of the ewe's organism. This work focused on the observation of selected indices during synchronization treatment and in the first days of pregnancy The experiment included 10 conventionally bred animals. Blood was obtained from the v. jugularis into an oxalate mixture on days 0 (date of synchronization), 3, 7 and 14 of Agelin implantation, on the day of oestrus and days 7, 14, 17 and 34 of pregnancy. Erythrocyte counts were determined by the Bürker flask method, hemoglobin concentrations by spectrophotometry and packed cell volume (PCV) by the method of Janetzki. For leucocyte count determination the Bürker flask method with Turk's solution was used; the percentual proportion of leucocytes was stated by the leucogram. During synchronization treatment and pregnancy the mean erythrocyte counts ranged from 9.16 +/- 0.81 to 9.74 +/- 0.61 T/l and from 9.09 +/- 0.84 to 9.47 +/- 1.11 T/l, respectively. Hemoglobin concentrations oscillated between 10.71 +/- 1.02 and 11.83 +/- 1.01 g/l. PCV values reached between 32.44 +/- 2.18 and 39.33 +/- 2.73 l/l with a significant increase on day 14 of Agelin implantation and days 17 and 34 of pregnancy (P < 0.05). This dynamics of the red blood components points to the occurrence of functional-morphological changes in the sexual apparatus during oestrus and Agelin treatment. Through mediation by the vascular system a change in the mean values may also occur (Kresan et al., 1979).(ABSTRACT TRUNCATED AT 250 WORDS)

[Characteristics of protein-protease inhibitors, 17-beta estradiol and progesterone in the blood of heifers returning to estrus following LH/FSH-RH treatment]. / Charakteristika korelácie proteín-proteázových inhibítorov, 17-beta estradiolu a progesterónu v krvi prebiehajúcich sa jalovíc po osetrení LH/FSH-RH.

Tests were performed to study the inhibitive capacity of protein-protease inhibitors, 17-beta estradiol, and progesterone in the blood serum of 21 heifers returning to oestrus which had been treated intramuscularly with 400 microgram LH/FSH-RH. Four selected heifers were examined as to the relationships between the concentrations of 17-beta estradiol, progesterone and the inhibitive capacity of the serum. Heifer no. 1 had low concentrations of 17-beta estradiol and higher concentrations of progesterone (average levels 7.8 and 657.4 pg ml-1 of serum). On the other hand, heifer no. 4 was found to have higher concentration of 17-beta estradiol and lower values of progesterone (average levels 28.3 and 325 pg ml-1 of serum). Having shown heat, the heifers were fertilized and remained in calf. Heifer no. 2 with a low concentration of progesterone (292 pg ml-1 of serum) and 17-beta estradiol (12.4 pg ml-1 of serum), as well as heifer no. 3 with a high concentration of both (830 pg ml-1 of serum and 22.7 pg ml-1 of serum, respectively) showed no heat and they were not mated. Heifers with significant differences in the concentrations of progesterone and 17-beta estradiol and with low values of protein-protease inhibitory capacities remained in-calf, whereas heifers with lower progesterone and 17-beta estradiol values, or adversely, with higher inhibition values, showed no heat. Synthetic LH/FSH-RH was found not to increase the amount of protein-protease inhibitors in heifer serum, as distinct from the cervical mucus of breeding cows treated with gestagens in heat synchronization.

[The effect of synchronization on estrus and pregnancy in sheep and on levels of thyroxine, triiodothyronine, 17 beta-estradiol, progesterone and cholesterol]. / Vplyv synchronizacného osetrenia v sezónnom období a v gravidite oviec na koncentrácie tyroxínu, trijódtyronínu, 17 beta-estradiolu, progesterónu a cholesterolu.

Knowledge of pathogenesis of sexual dysfunctions at altered thyroid activity is limited by the knowledge of multiple and ubiquitous action of its hormones throughout the organism. One of the possibilities of modulatory influence of thyroid hormones on sexual functions can be realized through the participation of thyroxine and triiodothyronine in the synthesis and metabolism of primary substrate of steroid synthesis--cholesterol. The presented work is aimed at the study of simultaneous dynamic changes of concentrations of thyroxine (T4), triiodothyronine (T3), 17 beta-estradiol (E2), progesterone (P4) and cholesterol (Chol) during synchronization of the rutting period and gravidity at parallel correlative evaluation of mutual relations of the followed parameters in ten Merino sheep in the seasonal period. Synchronization was achieved by chlorsuperlutin (Agelin--vaginal swabs, Spofa; 20 mg of chlorsuperlutin/swab) and PMSG (500 I. U./animal). Blood was sampled by means of a jugular vein puncture at the time of swab insertion (-13th day) and after three (-10th day) and seven (-7th day) following days, at the removal of swabs and application of PMSG (-3rd day), on the day of insemination (zero day), on the 7th, 14th and 17th day and in the middle of the 2nd, 3rd, 4th and 5th month of gravidity. In the phase of oestrus synchronization a significant increase of E2 concentrations on days -7 and -3 of the experiment (0.47 +/- 0.079 and 0.542 +/- 0.177 nmol.l-1 of serum, P less than 0.001; P less than 0.001) was observed compared to the E2 values on day -13 (0.084 +/- 0.036 nmol.l-1 of serum). Parallel to these observations, marked intermittent changes of T4 (Tab. I, Graph 1) were recorded with the lowest values of this parameter observed on days -10 (41.75 +/- 20.23, P less than 0.05) and -3 (50.22 +/- 18.77, P less than 0.05) and the highest on day -7 (96.77 +/- 17.51 nmol.l-1, P less than 0.01) and day zero (85.40 +/- 19.59 nmol.l-1 of serum, P less than 0.05) in comparison with the -13th day (67.22 +/- 18.29 nmol.l-1 of serum). Concentrations of P4 (Tab. I, Graph 4) declined to the lowest values on day zero observation (0.09 +/- 0.08 nmol.l-1 of serum, P less than 0.05 vs 3.40 +/- 3.61 nmol.l-1 on day -13). No significant changes of concentrations of T3 (Tab. I, Graph 2) and Chol (Tab. I, Graph 5) were observed during oestrus synchronization. During gravidity, concentrations of E2 (Tab. I Graph 3) showed an increasing trend compared to the -13th day.(ABSTRACT TRUNCATED AT 250 WORDS)

[Levels of sodium and potassium and their relation to ovarian hormones during estrus synchronization and pregnancy in ewes]. / Koncentrácie sodíka, draslíka a ich vztah k ovariálnym hormónom v case synchronizácie ruje a gravidity bahníc.

The active transport of mineral substances by cell membranes plays an important role in the neurohumoral regulation of reproductive processes in farm animals. A great importance is attributed to lipoproteins as sources of the primary precursor of steroid synthesis in the placenta and ovaries (Knopp et al., 1986; Grummer et al., 1988). The effects of hormones on K metabolism in the blood serum of ewes were studied by Hawk et al. (1961). Krajnicáková et al. (1993) observed the dynamic changes of electrolytes in the course of the reproductive cycle in ewes. Na and K levels and their relation to ovarian hormones were determined in the systemic blood stream of ewes during oestrus synchronization and pregnancy. Ten Slovak Merino ewes aged 3-5 years and weighing 40-50 kg were included in the experiment. The animals were reared conventionally. A feed ration consisted of silage, hay, feeding beet-pulp, straw and in the last two months of pregnancy it was supplemented with roughage. Water and salt were given ad libitum. Blood samples were obtained from the jugular vein prior to synchronization (day 0) and on days 3, 7 and 14 of synchronization with Agelin vaginal implants. After removing the implants the animals received 500 I.U. PMSG (Pregnant Mare Serum Gonadotropin). The animal in oestrus cycle were inseminated with fresh diluted semen. Reinsemination was not performed in this experiment. Sampling was continued on the day of insemination and on days 7, 14 and in month 2, 3, 4 and 5 of pregnancy. Na and K levels were measured by atomic absorbtion spectrophotometry using the Atom Spek device (RANG-HIGLER). Progesterone (P4) and 17 beta-oestradiol (E2) levels were assayed radioimmunologically using the respective kits (RIA-test-PROG and RIA-test-ESTRA) manufactured by URVJ Kosice. During the observation period Na levels fluctuated within 131.50 +/- 1.71 and 153.55 +/- 4.77 nmol/l of serum (Tab. I) and significantly decreased between day 14 of synchronization and the end of the investigation (P < 0.05; P < 0.01; P < 0.001). Potassium levels were observed to significantly decrease from the day of insemination on, throughout the first days of pregnancy and the above-mentioned months of gravidity, the values ranging between 4.57 +/- 0.52 and 3.93 +/- 0.36 nmol/l.(ABSTRACT TRUNCATED AT 400 WORDS)

[Levels of total lipids, cholesterol and progesterone during estrus synchronization and pregnancy in sheep]. / Koncentrácie celkových lipidov, cholesterolu a progesterónu v case synchronizácie ruje a v priebehu gravidity oviec.

Our investigations were concerned with dynamic changes in total lipids (CL), cholesterol (CHOL) and progesterone (P4) in blood serum of sheep in the period of oestrus synchronization treatment and during mating and gravidity. Our experiment was carried out using 10 animals housed under the conditions of productive rearing. Blood samples were taken from v. jugularis on day of swab application (day 0) and on days 3 and 7 of the action of Agelin vaginal swabs, on day of insemination, and on days 7, 14, 17 and in the 2nd, 3rd and 4th month of gravidity. Blood serum was used to determine total lipids and cholesterol by means of Bio-Lachema tests, and P4 concentrations employing RIA-test-Prog kits (URVJT, Kosice). A statistically significant decrease in concentrations of total lipids (Fig. 1, Tab. I) in sheep blood serum was recorded on day of insemination (P < 0.05) compared to day 0, with the value 1.59 +/- 0.31 g/l of serum, and in the 3rd month of gravidity (P < 0.01), at concentrations 1.36 +/- 0.38 g/l of serum. The determined decrease in their values in the mentioned period can be modulated by the mutually changing ratio of steroid hormones or by inhibition of synthesis of lipoproteins responsible for changes in total plasma lipids. Changes in cholesterol concentrations (Fig. 2, Tab. I) during the introduction of swabs were insignificant and ranged from 1.60 +/- 0.42 to 1.73 +/- 0.33 mmol/l of serum. An insignificant increase in cholesterol concentrations (P < 0.05), with its highest levels 1.98 +/- 0.43 mmol/l of serum, was recorded in the 3rd month of gravidity.(ABSTRACT TRUNCATED AT 250 WORDS)

[Alkaline phosphatase during the puerperium in ewes and its relation to thyroid hormones and ovarian steroids]. / Alkalická fosfatáza v puerpériu bahníc a jej vztah k hormónom stítnej zl'azy a ovariálnym steroidom.

Triacylglycerols as the sources of cholesterol, the primary precursor of steroid synthesis, are one of the factors that limit the speed of steroidogenesis. Synthesis and resynthesis of triacylglycerols depend, in addition to other factors, on phosphatid hydrolysis that is controlled during pregnancy by placentary ALP (Sumikawa et al., 1987) and the FFA pool in the systemic blood stream. Enzymes participating in FFA release from the fat tissue are affected by thyroid hormones and TSH (Mayes, 1977). In view of the above facts, this work was aimed at the observation of changes in alkaline phosphatase (ALP), thyroxine (T4), triiodothyronine (T3), 17 beta-oestradiol (E2) and progesterone (P4) levels and their mutual correlations in the systemic blood stream of sheep from the first day after parturition to day 51 p.p. Our attention was paid to the possible delayed effects of placentary ALP and thyroid hormones on the synthesis of ovarian steroids in puerperal ewes. Nine merino sheep were included in the experiment; they lambed in the first decade of February and were kept together with their lambs in a classical sheep-cot on deep litter. The animals were fed according to the Czechoslovak State Standard CSN 46 7070. Blood samples were taken from the v. jugularis from 8 to 9 o'clock a.m. 24 hs (day -1) prior to parturition (a.p.), 36 hs and on days 4, 7, 14, 17, 21, 25, 34, 42 and 51 after parturition (p.p.). As compared with day -1 (2.6 +/- 1.08 mu kat/l), ALP concentrations showed a decrease with minimum values occurring on day 17 (1.34 +/- 0.97 mu kat/l, P < 0.05). T4 concentrations also decreased from day -1 (59.4 +/- 9.69 nmol/l) to day 21 (54.89 +/- 11.06 nmol/l, P < 0.05). A similar decrease (from 1.82 +/- 0.33 nmol/l on day 1 to 0.85 +/- 0.32 nmol/l on day 21) could also be observed in T3 levels. As early as 36 hs p.p., the concentrations of both steroid hormones, E2 and P4, significantly decreased [from 2.45 +/- 0.65 and 9.46 +/- 0.34 nmol/l on day -1 to 0.30 +/- 0.24 and 0.05 +/- 0.08 nmol/l, respectively (P < 0.001)]. Throughout the period of investigation, apart from an unsubstantial increase in E2 values on days 17 and 42 and an episodic increase in P4 levels on day 34, the concentrations of both steroids had the values that were significantly lower than those observed on day -1.(ABSTRACT TRUNCATED AT 400 WORDS)

[Thyroid and ovarian hormones in ewes treated with gestagens and PMSG in the spring season]. / Hormóny stítnej zl'azy a vajecníka u bahníc osetrených gestagénmi a PMSG v jarnom období.

Recent experimental observations have shown that the thyroid gland plays a dominant part in the induction and maintenance of anoestrus in ewes. The mechanisms of the anoestrous effects of the thyroid gland are still unclear. On the basis of experiments, in which after thyroidectomy at the onset of sexual activity LH production was maintained also during the spring months, iodothyronines have been supposed to stimulate the inhibitory effects of oestrogens upon the neuroendocrine centres that generate pulsatile LH secretion (Moenter et al., 1991; Webster et al; 1991). However, in our previous work (Bekeová et al., 1995) we observed significant changes in iodothyronine levels, mainly T3, in ewes treated with FSH, LH-RH and oxytocin-based preparations in 24 and 72 h after parturition in the spring. Having made the above observations we suppose seasonal anoestrus to result rather from changes in thyroid and ovarian hormone interactions or from a decrease in thyroid hormone levels that is induced by a temporary decrease in sexual hormones in this phase of the year. Within investigations into the effects of thyroid hormones and their interactions in spring this study focused on the response of the thyroid gland and ovaries in anoestrous ewes to chlorsuperlutin and PMSG treatment in the second half of May. Eighteen Slovak Merino ewes were divided into an experimental and a control group counting 15 and 3 animals, respectively. The experimental animals were each treated with 20 mg chlorsuperlutin (Agelin Spofa vaginal inserts) for 12 days. On day 12 the inserts were removed and each animal was given 500 IU PMSG. In the same time intervals the controls were treated with a placebo (sterile polyurethane, saline). Blood samples were obtained prior to swab insertion (day 0) and in 4-day intervals under chlorsuperlutin treatment (days 4, 8 and 12). For the first 24 h after PMSG-treatment blood samples were taken in 2-hour intervals and then in 48 and 72 h. For radioimmunological determination of T4, T3, E2 and P4 levels the RIA-test-T4, RIA-test-T3, RIA-test-Estra and RIA-test-Prog commercial kits (manufacturer: URVJT Kosice, Slovak Republic) were used, respectively. When compared to the almost constant but significantly lower T4 values in the controls (P < 0.05; P < 0.01; Tab. II, Fig. 1), a repeated massive release of T4 occurred in the experimental animals (Tab. I, Fig. 1). Its first peak observed 4 h after PMSG was significant in comparison both to Day 0 and the controls (P < 0.05 and P < 0.01, respectively). The same was true for the 2nd peak observed 20 h after PMSG-treatment (P < 0.001 and P < 0.01, respectively). The dynamics of T3 was similar in both groups. The transitory increase in T3 levels observed in the controls (Tab. II, Fig. 2) on day 4 of chlorsuperlutin treatment was insignificant when compared to day 0. Both the decrease observed between day 8 and of chlorsuperlutin treatment and 20 h after PMSG gavage, and the increase between 24 and 72 h appeared to be insignificant. Comparison to day 0 revealed increased T3 levels in the experimental group (Tab. I, Fig. 2) on days 4 and 8 of chlorsuperlutin treatment, the levels of significance being P < 0.01 and 0.05, respectively. Between 8 and 24 h after PMSG-gavage, in contrast to the controls, T3 levels in the experimental animals acquired the character of a slowly increasing rhythmic pulsation. At 72 h after PMSG a significant decrease occurred (P < 0.05). In the control animals (Tab. II, Fig. 3) E2 levels revealed interchanging episodes of insignificant increase and decrease beneath test sensitivity. In the experimental ewes (Tab. I, Fig. 3) a double-peaked elevation of E2 could be observed, the first (insignificant) peak occurring 18 and 20 h and the second (significant) one 48 and 72 h following PMSG treatment (P < 0.05 and 0.01, respectively). The inter-group differences were significant at the level of P < 0.05 in each case.

[Concentration of progesterone and thyroxine in the luteal phase of the cycle in heifers after administration of estradiol benzoate]. / Koncentrácia progesterónu a tyroxínu v luteálnej fáze cyklu jalovíc po ovplyvnení estradiol benzoátom.

The effect of current 48-hour infusion of estradiol benzoate (EB) on the dynamics of the concentration of progesterone (P) and thyroxine (T4) was studied in four heifers in the luteal stage of their cycle. The parameters were evaluated in three intervals: infusion (A), post-infusion (B) and "uninfluenced" interval (C). In the course of infusion the concentrations of P in three animals had a markedly descending tendency. The P concentration increase in the 36th hour of infusion was maintained also during the post-infusion interval. The decrease in P in the third, "uninfluenced", interval was replaced by a new rise towards the end. One heifer showed an increase in P concentrations at the beginning of EB infusion. A decrease was recorded towards the end of the interval. The concentration decreased in the post-infusion period. A comparatively high concentration of P in the "uninfluenced" interval was again replaced by a drop towards the end in the 286th hour. The concentration of T4 in three heifers had a descending tendency in the infusion and post-infusion intervals. The decrease in the infusion interval was more pronounced. In the "uninfluenced" interval the T4 concentrations increased step by step. In one heifer the concentration of T4 slightly increased during infusion. A decrease was recorded in the post-infusion and "uninfluenced" interval. Rectal examination in the 172nd hour revealed the original corpus luteum in three animals and the production of the corpus luteum in the same ovary was found in this period in one heifer. In the 88th hour this animal showed clinical manifestations of oestrus. On the basis of the dynamics of the studied hormones and clinical studies, the thyroid hormones can be regarded as an important secondary factor involved in the permanent cyclic changes in reproduction process.

[The follicular system of bovine ovaries after estrus synchronization using the luteolytic action of cloprostenol]. / Folikulárny systém vajecníkov kráv po synchronizácii ruje luteolytickým pôsobením cloprostenolu.

Oestrus synchronization was studied in samples from six cows of the Black-Pied Lowland breed. Three cows four to five days from oestrus were used as the control; three animals with marked periodic corpora lutea were given an i. m. injection of 0.5 mg cloprostenol. The eighth day from the administration of the preparation, the ovaries of the cows were excised and, after histological processing in a simultaneous series in a 4mm interval, the preparations were subjected to qualitative and quantitative microscopic evaluation. The structure of non-atretic and atretic follicles was described in different stages of the atretic process. The lymphoid cells of atretic follicles were observed to penetrate into the granulosa membrane. A multiplication of non-atretic tertiary follicles was observed after the administration of cloprostenol. This multiplication was more pronounced on the right ovary where the preceding ovulation had taken place (P less than 0.01). The treated animals, compared with the controls, showed a significant multiplication of tertiary follicles at early atresia and at total collapse atresia (P less than 0.001), whereas the number of follicles with contractive atresia showed a significant decrease (P less than 0.001). The results suggest that cloprostenol can influence follicle population mostly through the stimulation of the growth and ripening of tertiary follicles; its modulation effect seems manifest itself in cooperating relation with gonadotrophic hormones, mainly with the follicular secondary hormone (FSH), in the theory of the complex effect of proteohormones .

[Changes in surface follicles and ovarian weight in testing for responsiveness in dairy cows after induction of superovulation using PMSG and cloprostenol]. / Zmeny povrchových folikulov a hmotnosti vajecníkov pri testovaní responzibility dojníc po indukcii superovulácie PMSG a cloprostenolom.

We evaluated the ovaries of 34 cows cross-bred of the Slovak Pied and Lowland Black-pied breeds which were culled and intended for slaughter during the winter type of feed rations. For superovulation treatment we used PMSG in the preparation Serum Gonadotropin (Bioveta, Nat. Ent., Ivanovice na Hané) and cloprostenol in the preparation Oestrophan inj. Spofa. We weighed the excised ovaries, fixed them in formalin 10% and made a quantitative evaluation of the surface follicles and differentiated them into recruited and selected or dominant follicles. We determined the concentration of 17 beta-estradiol and testosterone with the aid of the 3H RIA set from the firm Sorin after extraction by diethylether with separation of free and bound hormone with active charcoal. 72 hours after the giving of cloprostenol 43% reacted positively to superovulation treatment and after seven days a 50% positive response was recorded. After a dose of 2000 i. u. of PMSG (n = 6) embryo was obtained, whereas after 3000 i. u. of PMSG (n = 8) we flushed out eight embryos, of which four zygotes were suitable for transfer. After a higher dosage of PMSG there was an increase in the average weight of the ovaries, in right-hand ovaries significantly with P less than 0.05. After super-ovulation treatment the concentration of 17 beta-estradiol (E2) in the follicular fluid from follicles seven days after insemination was found to be so low as to be below the limit of detection, with the exception of four samples (mean = 8.60 nmol.l-1). The greatest concentration of E2 was from animals (n = 5) 72 hours after the giving of cloprostenol--1099.61 nmol.l-1) of follicular fluid. The concentration of testosterone was lower in the follicles of untreated cows in the follicular phase (mean = 5.92 nmol.l-1) compared with the follicles of super-ovulated animals the seventh day after insemination (mean = 14.12 nmol.l-1). The number of recruited and especially selected surface antral follicles 72 hours (n = 7) after the giving of cloprostenol and seven days (n = 8) after insemination was significantly higher in the group of brood cows reacting positively to superovulation in comparison with the animals which did not respond. It appears that the simultaneous monitoring of hormonal and morphological changes in the follicular system will help in objectivising the evaluation of the functional activity of stimulated follicles.

[Histology of the oviduct epithelium of dairy cows after estrus synchronization with cloprostenol]. / Histológia epitelu vajcovodu dojníc po synchronizácii ruje cloprostenolom.

After fading away of the effect of cloprostenol contained in the Oestrophan inj. Spofa preparation, the qualitative and quantitative changes in the epithelium of oviduct ampulla and isthmus of dairy cows were studied. Three dairy cows in the fourth to fifth day after heat were used as control, three cows with the rectally palpated active corpus luteum were given 0.5 mg cloprostenol i. m. On the eighth day after treatment, samples were taken from ampulla and isthmus by means of necropsy. After histological treatment, the samples were evaluated microscopically. Histological staining with hematoxylin-eosine, PAS reaction and PAS reaction with nucleus staining with Harris hematoxylin were used to describe the occurrence of the so-called pale cells. In accordance with the literary data, these cells are believed to be intraepithelial lymphocytes, the function of which will have to be further researched and determined objectively. On the eighth day after cloprostenol administration or on the fourth to fifth day after ovulation in the ipsilateral ovary, a significant decrease in epithelium thickness close to infundibulum and in the depth of ampulla (P less than 0.001) was observed. The changes in the contralateral left side were not significant. After cloprostenol application, the multiplication of nail-like cells in the right-side oviduct ampulla was statistically significant (P less than 0.05).

[Dynamics of changes in the cytological picture of vaginal smears and circulating ovarian hormones during the puerperal period in ewes]. / Dynamika zmien cytologického obrazu posvového steru a ovariálnych hormónov cirkulujúcej krvi v puerperálnom období bahníc.

A postparturient period is characterized by low basal secretion of adenohypophysis gonadotropins with the following appropriate changes in ovarian hormones and their response to the morphology of vaginal epithelium. In this study the dynamics of the cytological picture of vaginal swabs and ovarian hormones 17 beta-oestradiol (E2) and progesterone was investigated in the puerpery of ewes. The objective was to obtain and extend the knowledge of cytological changes in vaginal epithelium and levels of ovarian hormones of ewes after parturition and of their relationships from the first several days after lambing until the 51st day of the period of observation. Vaginal swabs for vaginal cytology were taken from nine ewes on days 1, 4, 7, 14, 17, 21, 25, 34, 42 and 51 after parturition. These swabs were fixed in ether-alcohol 1:1, stained according to the Faltínová-Zidovský method, embedded in Canada balsam and evaluated by differentiation of cells according to Luksh (1953). Blood samples for E2 and P4 determinations were taken from the jugular vein in the same intervals as vaginal swabs. The serum was centrifuged and stored at -18 degrees C until use. E2 and P4 concentrations were determined radioimmunologically, using kits RIA-test ESTRA and RIA-test PROG from URVJT Kosice. A statistically significant decline (P < 0.05) of percentual representation of basal and parabasal cells (Fig. 1, Tab. I) on day 7 after lambing was replaced by their multiplication from day 14 reaching the values of 66.07 +/- 3.95 on day 42. A statistically significant decrease in intermediary flat cells (Fig. 2, Tab. II) was observed on days 14 (P < 0.001), 34 and 42 (P < 0.01; P < 0.001), in comparison with the first day after lambing. An evaluation of intermediary convoluted cells revealed their highest percentage on days 1 and 17 after parturition (34.65 +/- 4.77-20.62 +/- 12.57) and their decline to values in the range of 6.77 +/- 1.46-7.66 +/- 2.25 on the remaining days of the period of observation. Percent occurrence of superficial flat cells (Fig. 3, Tab. I) ranged from 3.9 +/- 1.10 to 10.63 +/- 7.23 from day 1 to day 51 after lambing. The lowest percentual representation (1.32 +/- 0.79-4.10 +/- 1.89) was recorded for superficial convoluted cells. Multiplication of the evaluated cells was observed, reaching the highest but insignificant representation (P > 0.05) on day 25 of postparturient investigation: 4.10 +/- 1.89 (Fig. 3, Tab. I). 17 beta-oestradiol (E2) concentrations were compared to the -1st day before parturition, when its values varied at the level of 2.45 +/- 0.64 nmol/l serum.(ABSTRACT TRUNCATED AT 400 WORDS)

[Thyroxine and progesterone levels in cows and heifers after administration of Oestrophan (Spofa) in the luteal phase of the cycle]. / Hladiny tyroxínu a progesterónu u kráv a jalovíc po podaní oestrophanu (Spofa) v luteálnej fáze cyklu.

Thyroxine and progesterone levels were studied in cows and heifers in the luteal stage of the cycle after the application of the synthetic analogue of prostaglandine of group F2 alpha: Oestrophan Spofa. The preparation was administered at a rate of 0.5 mg in 2 ml per animal. The thyroxine and progesterone levels were determined radioimmunologically. The administration of Oestrophan led to a reduction in the progesterone level from the initial value of 17.33 +/- 2.73 nmol/l of serum to 7.69 +/- 1.17 nmol/l of serum an hour after the application, followed by slow decrease below the value 1.59 +/- 0.22 nmol/l of serum at the 24th hour. The initial levels of thyroxine with the average values of 122.11 +/- 23.41 nmol/l of serum were comparatively high. An hour from application of the preparation, a significant decrease to the average levels of 88.14 +/- 16.26 nmol/l of serum (P less than 0.05) was recorded with a significant negative correlation. The correlation coefficient r = -83316, P less than 0.01. The thyroxine level decreases to the values of 24.20 +/- 9.26 nmol/l of serum and 24.12 +/- 6.68 nmol/l of serum, P less than 0.01, at the 52nd to 56th hour, i. e. at the time when the pre-ovulation peak of oestrogens can be expected. A statistically significant correlation--even despite the fact that a highly significant decline in thyroxine and progesterone had been observed--was recorded in none of the cases in the subsequent period of study, except the first hour. It can be assumed from the results that the thyroid hormones are among the links acting at more levels of the regulatory biological circuit responsible for the physiological course of ovulation and reproduction process.

[Dynamics of changes in the serum levels of cholesterol, thyroid and ovarian hormones in the postpartum period in ewes]. / Dynamika zmien koncentrácie cholesterolu, tyroidných a ovariálnych hormónov krvného séra v postpartálnom období bahníc.

Postparturient anoestry, spontaneously changing over to seasonal anoestry, represents an important reserve of full utilization of the reproductive potential of sheep. In spite of the fact that the length of gestation in sheep only amounts to 148 days (+/- 5 days), inability of most sheep to enter the cycle during the spring season acts as a factor limiting the number of lambings--and at the same time production of lambs--to one lambing per year. In order to obtain more detailed knowledge of hormonal conditions in sheep puerpery, the presented work was directed at the study of dynamic changes in concentrations of thyroxine (T4), triiodothyronine (T3), 17 beta-estradiol (E2), progesterone (P4) and cholesterol (Chol) in the blood serum of ewes and at their mutual correlative dependences between the 36th hour and the 51st postparturient day. The observation was carried out in nine nursing ewes of the Slovak Merino breed, with average weight 40-50 kg, lambed in January and February. Blood was sampled by means of jugular vein puncture 14 days (-14th day) before parturition (a. p.), up to 36 h after parturition (p. p.) and on day 4, 7, 14, 17, 21, 25, 34, 42 and 51 p. p. In the period from the 36th h to day 21 p. p., concentrations of T4 (Tab. I, Fig. 1) showed a decreasing tendency compared to the starting -14th day (69.55 +/- +/- 0.12 nmol.-1) with the exception of a temporary increase on the 7th day p. p. The lowest values were recorded on days 4 and 21 p. p. (45.66 +/- 21.61 nmol.l-1, P less than 0.05 and 54.89 +/- 11.06 nmol.l-1, P less than 0.05, resp.). An increase of these values to the starting level was observed between days 25 and 51 p. p. Compared to the values on -14th day (0.76 +/- 0.22 nmol.l-1), a significant increase of T3 concentrations (Tab. I, Fig. 2) was recorded at the 36th h and on days 4 and 7 p. p. with the highest values (1.48 +/- +/- 0.34 nmol.l-1, P less than 0.001) at 36 h p. p. After the temporary decrease between days 14 and 21 p. p. its concentrations showed a constantly rising tendency statistically significant on days 34, 42 and 51 p. p., compared to the -14th day (P less than 0.05). Concentrations of E2 (Tab. I, Fig. 3) reached the values of 0.44 +/- 0.41 nmol.l-1 on the -14th day.(ABSTRACT TRUNCATED AT 400 WORDS)